U.S. Sens. Michael Bennet, D-Colo., and Jerry Moran, R-Kan., led a bipartisan group of senators this week to urge the Internal Revenue Service (IRS) to quickly clarify rules relating to the renewable energy production tax credit (PTC).

Wind energy developers are awaiting further guidance on what it technically means to "begin construction" on their projects. (The PTC extension included a change in language that requires projects to begin construction before Jan. 14, 2014, in order to qualify for the PTC, rather than the "placed in service" deadline included in previous versions of the PTC.)

“The new iteration of the PTC and ITC will allow the United States to continue to diversify its energy portfolio through new generation from clean energy sources,” the senators wrote in a letter to Neal S. Wolin, acting secretary of the Department of the Treasury, and Steven T. Miller, acting commissioner of the IRS. “However, a lack of clear IRS guidance regarding the construction threshold and criteria necessary to claim the incentives may soon result in uncertainty among potential investors.”